Three-Component Difunctionalization of Cyclohexenyl Triflates: Direct Access to Versatile Cyclohexenes via Cyclohexynes
Difunctionalization of strained cyclic alkynes presents a powerful strategy to build richly functionalized cyclic alkenes in an expedient fashion. Herein we disclose an efficient and flexible approach to achieve carbohalogenation, dicarbofunctionalization, aminohalogenation and aminocarbonation of readily available cyclohexenyl triflates. We have demonstrated the novel use of zincate base/nucleophile system for effective formation of key cyclohexyne intermediates and selective addition of various carbon and nitrogen nucleophiles. Importantly, leveraging the resulting organozincates enables the incorporation of a broad range of electrophilic partners to deliver structurally diverse cyclohexene motifs. The importance and utility of this method is also exemplified by the modularity of this approach and the ease in which even highly complex polycyclic scaffolds can be accessed in one step.
Cho, Seoyoung,McLaren, E. J.,Wang, Qiu
supporting information
p. 26332 - 26336
(2021/11/10)
UROKINASE INHIBITORS
Disclosed are benzothiophene and thienothiophene derivatives useful for inhibiting urokinase activity.
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(2008/06/13)
BESTIMMUNG DER IONENPAAR-BASIZITAT VON LITHIUM- UND KALIUMAMIDEN
Ion pair basicities of lithio and potassio salts of some secondary amines were determined by equilibration with benzyl compounds.With these bases it is possible to span a range of about 19 pK-units from pK = 27 up to 46.The structural dependence of thermodynamic as well as kinetic basicity is discussed.Some new effective amide bases for preparative purposes are recommended.For the first time the pK-value of toluene has been determined by direct equilibration.It amounts to 40.7 in tetrahydrofuran.
Ahlbrecht, Hubertus,Schneider, Gunther
p. 4729 - 4742
(2007/10/02)
Acidity Measurements on Pyridines in Tetrahydrofuran Using Lithiated Silylamines
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Fraser, Robert R.,Mansour, Tarek S.,Savard, Sylvain
p. 3232 - 3234
(2007/10/02)
LITHIUM DIALKYLAMIDES. 13C PARAMETERS AND SLOW PROTON TRANSFER
The changes in 13C chemical shifts for the structural change R2NH -> R2N-Li have been measured for a series of dialkylamines.These lithiation shifts are largest at the alpha carbon (3.7-9.7 ppm) and decrease in the order α > β > χ > δ.The rates of lithium-hydrogen interchange between R2NH and R'2N-Li have been determined.The activation energies are large (9 - 17 kcal/mole) and increase as the size of R or R' increases.The slow exchange permits the direct measurement of acidity differences between pairs of amines using 13C nmr.
Fraser, Robert R.,Baignee, Alison,Bresse, Monique,Hata, Kazumi
p. 4195 - 4198
(2007/10/02)
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